1. Field of the Invention
The invention relates to means for data recording and reading and, more particularly, to optical memories or storage devices.
2. Description of the Related Art
Known in the art is an optical memory comprising a source of modulated electromagnetic radiation (gas laser), a photodetector, one working station for an optical disk data carrier as well as a library of the optical disk data carriers and a means for transferring thereof to, and from the working stations. The use of the optical disk data carrier makes it possible to provide a direct access to data and, hence, somewhat reduce the time for access to data (EP, B, 0106570).
A disadvantage of this solution resides in that the access time which comprises the time for transferring, inserting, accelerating, stopping and removing the optical disk data carrier remains too long. Another disadvantage resides in poor reliability of recording and reading since the working station is provided with only one optical head, the failure of which will make data recording and reading impossible.
Known in the art is an optical memory comprising the following optically coupled members: modulated electromagnetic radiation sources using laser diodes, photodetectors, and sixteen working stations for optical tape carriers placed in sealed cassettes each having an informational capacity of 6 Gbytes as well as a library of the tape data carriers and a means for transferring thereof to, and from, the working stations. (Mini-Macro Systems, June, 1984, Keith Jones "DOC data plans to make 6,000 M-byte optical-type cassette" pp. 98, 101).
In this memory, the time for access to data is from 1 to 10 s which results from a consecutive access to data on the tape carrier. Another disadvantage resides in poor reliability of recording and reading since each data carrier working station is provided with only one optical head, the failure of which will make recording and reading impossible.